Electrical permutation selector switch



Aug. 14, 1956 R. L. BERKE ELECTRICAL PERMUTATION SELECTOR SWITCH 4 Sheets-Sheet 1 Filed March 10, 1953 m VENTOR.

L. BERKE ATTO NEYS 1 B RALPH 14, 1956 R. L. BERKE ELECTRICAL PERMUTATION SELECTOR SWITCH 4 Sheet-Sheet 2 Filed March 10, 1953 INVENTOR RALPH L. BERKE Aug. 14, 1956 R. BERKE ELECTRICAL PERMUTATION SELECTOR SWITCH 4 Sheets-Sheet 3 Filed March 10. 1953 INVENTOR. RALPH L. BERKE BY Jmwaw wu.

ATTORN EYS 1956 R. L. BERKE ELECTRICAL PERMUTATION SELECTOR SWITCH 4 Sheets-Sheet 4 Filed March 10, 1953 INVENTOR.

RALPH L. BERKE ATTO N EYS United States Pateiit O 2,759,046 ELECTRICAL PERMUTATION SELECTOR SWITCH Ralph L. Berke, Chicago, Ill., assignor to Kleinschmidt Laboratories, Inc., Deerfield, 111., a corporation of Delaware Application that 10, 1953, Serial No. 341,560

14 Claims. (Cl. 178-33 The present inventionrelates to printing telegraph systems and apparatus and has to deal particularly with an electrical selecting device for the distribution of electrical pulses or signals in accordance with received signal permutations. p v f It is the principal purpose of this invention to provide a device of this character which may be incorporated in any printing telegraph system Whichutilizes a series of code elements operating on the well-known Baudot system of transmission to offer a means of selecting a particular electrical circuit for each character represented by the code being used.- This invention contemplates the use of the individual circuits for the selection of teletypewriter signaling channels but it is to be understood that the inyention is not to be limited, to such purposes but maybe used wherever a multiplicity of electric circuits controlled by a permutation code is practical.

, In its essential embodiment the invention consists of a group of non-conducting plates having electrical contacts distributed on and passing through them. The plates are stacked together and arecaused to move over one another to take either of two positions to correspond to marking or spacing currents of a signaling code. The contacts are so distributed that there will always'be only one lined up group of contacts running through the several plates so that when the back plate is pressed against a conductor a current is caused to be channelled through the aligned contacts.

In the present embodiment ofthis invention there are five non-conducting movable plates each containing thirty-two contacts, a back conducting plate in contiguity with all the contacts of the fifth plate and connected to a source of electric current, a stationary front plate con taining thirty-two contacts'each with a terminal for connecting it with its particular assignment which may be to operate a relay to select a typewriter signaling channel. it is to be understood that this invention is not limited to the five individual plates or thirty-two contacts above disclosed but may contain any number of plates and contacts depending on the signaling code to be used.

For a more comprehensive understanding of the present invention, reference should be made to the accompanying drawings in which:

Figure 1 is a perspective view of an electrical channel selector embodying the principles of the present invention;

Figure 2 is a plan view of the selector of Figure 1;

Figure 3 is a schematic view showing the cooperation of the electrical channel'selector of the present invention with the selecting mechanism of a printing telegraph apparatus such as is described in United States patent application No. 190,359, filed October 16, 1950;

Figure 4 is a perspective view illustrating the cooperation of the electrical channel selector of the present invention with a magnetic selecting mechanism; and

Figure 5 is a. perspective view illustrating the cooperation of the electrical channel selector of the present in- 2 vention with a perforated tape controlled selecting mechanism. I V I A detailed description of the electrical channel selector switch vwll now be given:

The unit as illustrated in Figures 1 and 2 has a terminal plate It} made of non-conducting material through which project a plurality of terminal posts generally indicated bythe number 12 and one specifically 215114, thirty-two such posts being shown in the illustrated em? bodiment. The outer end of each post has a terminal for attaching an electric lead or wire (not shown); the inner end has a shoulder 16 inabutment with the inner face of the plate 19. Thejarrangement ofthe terminal posts 12 may be one of any number of patterns, the one illustrated having rectangular form with four.lines of eight each. Each of the selector .plates 18,20, 22, 24, and 26 is made of non-conducting material such as that of the terminal plate 10 and is similar to it with the exception that each has attached at one end an extension 28 adopted for engagement withone of the suitable motivating means described hereinafter.

The plates 18, 20, 22, 24 and 26 are mounted for movement in a longitudinal direction which will be referred to as left and right positions hereinafter. Each of the plates 13, 20, 22, .24 and 26 is perforated to receive a plurality of pins, one of which is indicated at 30. Each pin 3! has an enlarged portion 32 which forms a shoulder to hold the pin within the plate when pressure is applied to the group of plates from the {back for a purpose to be described. The enlarged ends 32 of each of the pins- 30 also forms an electrical contact for engaging an aligned contact pin on the adjacent plate. The location and disposition of the pins 31) on each plate is predeterminedly designed so that for the the permutated placement of the five plates, each plate being capable of assuming one of two positions, there is afforded an individual alignment of contacts extending through them.

Each end of each of the code plates 18, 20, 22, 24 and 26 with their extensions 28 have elongated holes 19 (Fi ure 3) through which are received fixed posts 34, 3S and 36 thus supporting the plates andtheir extensions for reciprocation in left and right directions.

Behind the fifth code plate 26 is a conducting strip 38 with a projecting terminal 40 which may be connected to a source of electrical energy. This strip 38 is mounted on a larger plate 42 and insulated from it by a non-conductive plate .44 interposed therebetween. At each end of the mounting plate 42 is formed a. hole through which are received respectively the mountingposts 34 and 36 (Figure 2), permitting lateral reciprocation of the mounting plate 42 axially of the posts 34 and 36 while restraining the plate 42 against longitudinal movement. About the posts 34 and 36 are coil springs 46 and 47 respectively pressing at one end against the shoulders 48 and 49 of the mounting posts 34 and 36 and at theirother ends against the plate 42. Pressure exerted by these springs 46 and 47 normally holds the plate 42 and its associated conducting strip 38 out of contact with the enlarged ends 32 of the pins 30 on the fifth code plate 26. v

Attached to the rear face of the. plate 42 are two spaced wedges 5t) and 52. The sloping surfaces of the wedges 50 and 52 engage the sloping surfaces of a pair of mating wedges 54 and 56 which are mounted to alongitudinally reciprocable pressure plate 58. Holes (not shown) at the ends of the pressure plate 58, which mount it on the pins 34 and 36, are elongated to allow the pressure plate to be moved longitudinally under cam control. A slot 60 (Figure l) in the plate 58 is engaged by one leg 62 of a bell crank 63 pivoted 0n fixed post 64 and biased in a counter-clockwise direction as viewed'in Figure 2 by a spring 66 fastened at its opposite ends to the arm 68 of bell crank 63 and to a fixed spring stud (not shown).

A cam follower 70 formed on the end of the arm 68 is caused to rise by a cam 72 turning the bell crank 63 in a clockwise direction which will slide the pressure plate 58 to the left as viewed in Figures 1 and 2. As the pressure plate 58 moves to the left the wedge surfaces 50 and 54 slide causing the aggregate thickness to be greater and thus forcing the spring-pressed conductor strip plate 38 to move into contact with the enlarged ends 32 of the pins 30 on the fifth code plate 26.

The above described action of the pressure plate is timed to occur after the code plates have been set in their permuted positions as will be described hereinafter, thus minimizing excessive Wear on the contact pins 30. Electric current is applied to the contact strip or plate 38 only after pressure has been exerted in the manner described above. Arcing, which would exist if current were flowing as the contacts came together, is thus avoided.

In .the ,broader'aspects of the present invention, the setting of the code plates 18, 20, 22, 24 and 26 in their positions may be controlled by any suitable selecting mechanism. The three presently preferred selecting devices are illustrated in Figures 3, 4 and 5.

Figure 3 shows a selector mechanism adapted to receive intelligence in the form of coded electrical impulses and translate it into mechanical movement of the code plates in accordance with a received electrical impulse code group. In such a selector mechanism, a rotatable shaft 100, is kept in step or synchronism with the incoming signals by a start-stop mechanism which initiates the rotation of the cam shaft 100 in response to a starting line condition preceding each code group of impulses and stops the rotation of the cam shaft 100 in response to a stopping line condition following each code group of impulses. The selector mechanism includes a single selector magnet 102, responsive to line conditions instigated and controlled by a local or remote transmitter which sends intelligence in the form of electrical impulses whereupon the magnet 102 operates its armature 104 in conjunction with the rotatable cam shaft 100 to control the pivoted movement of a group of selector fingers 106 equal in number to the variable line conditions in one signal character code group. In the example referred to herein, five such fingers 106 are shown to work in accordance with the well known Baudot code. Signaling pulses from the line are received in the polar selector magnet 102 the right hand one of which attracts the armature 104 on marking pulses and releases it on spacing pulses at which time the left hand core attracts the armature 104. On marking pulses the armature 104 blocks one end 108 of the selector fingers 106 and on spacing pulses, as shown in Figure 3, the fingers 106 are unblocked. The five selector fingers 106 are affected by the rotating cams 109 on shaft 100 to positively position five selector levers 110 in accordance with the signals received. The release of a transfer lever 114 which is pivoted on shaft 115, brings a set of five T-levers 116 into simultaneous contact with the five selector levers 110. The T-levers 116 take the settings of the selector levers 110 and, as the upwardly projecting portion 118 of each T-lever engages a slot 120 in the corresponding extension 28 of each of the code plates 18, 20, 22, 24 and 26, the code plates are set in left and right positions corresponding to the code signal received. To impart the same settings as taken by the electrical code plates to a mechanical selecting mechanism as disclosed in copending application S. N. 190,359 of E. F. Kleinschmidt filed September 14, 1950, for Selector Mechanism, the extensions 28, of each code plate are provided with upwardly projecting arms 121 which engage depending spaced legs 122 of five circular permutation notched code rings 123 and, as these rings 123 are pivotly mounted relative to shaft 124, they will take clockwise or counter-clockwise settings which will permit one of the spring-pressed stop bars 126 to enter the aligned notches to arrest the movement of a rotatable stop arm (not shown) and position the associated selecting shaft 124 in accordance with the received signal. The positioning of the shaft may be utilized in any suitable manner for any desirable purpose such as operating certain electrical contacts, positioning a typewheel or type bar operating mechanism. If a more detailed explanation of this selecting mechanism is found to be necessary to a complete understanding of the present invention, reference may be made to the copending application aforesaid.

A magnetic means for setting the code plates 18, 20, 22, 24, and 26 is shown in Figure 4 of the drawings. The electro-magnetic solenoids 150, 152, 154, 156, and 158 each has its movable core 160 connected to one end 162 of an aligned one of a series of bell cranks 164. The five bell cranks 164 are pivoted on a common post 168. The operating arms of bell cranks 164 all extend in the same direction to engage the slots 120 in the aligned extensions 28 of the corresponding code plates 18, 20, 22, 24, and 26. In this example up and down reciprocatory movement of the plates takes the place of the left and right reciprocatory movements hereinabove described and are caused by clockwise or counter-clockwise turning of the corresponding bell cranks 164. Each of the bell cranks is biased by a spring 172 to be normally in their clockwise positions as viewed in Figure 4. The magnets 150, 152, 154, 156, and 158 are selectively energized by any suitable electrical distributing or control means such as are common to the art. Upon energization their cores will be pulled to the left causing the upper arms 162 of the bell cranks 164 to move to the left. The bell crank 164 is thus turned counter-clockwise which raises the leg 170 to set the code plate in its upper position as is illustrated for plates 20 and 26. A group of latches 174 act individually to lock the permuted settings of the associated code plates as soon as they are made so that de-energization of the magnets 150 will not disturb their set positions until all of them have been set and the permuted setting utilized by passing a current through the aligned contacts as described in the first part of this application. After the setting has been utilized, the plates are unlatched by the bail 176 operated by a cam 178 on the constantly rotating shaft 180. The cam 178 also acts to apply the pressure to the group of plates through a modified bell crank 63' as hereinabove described. An additional cam 182 on the shaft acts through the crank 184 to close the electrical contact 186 immediately after the pressure has been applied by crank 63'.

Referring now to Figure 5, a means for operating the selector switch from a signal recorded by perforations in a paper record strip will be described. A general description will be followed by a more detailed explanation.

A paper strip containing indicia in the form of perforations corresponding to current impulses of a signaling code is caused to move under a group of sensing pins which are raised and lowered in timed relationship to the longitudinal movement of the strip. As the group of five pins is lowered onto the strip, some may engage holes which will allow the pin to drop through and take a lower position than the others. The sensing pins are carried at the bottom of reciprocable members which have projections for engaging the tips of a group of T-shaped levers which are pivoted on the end of a transfer lever. The sensing members and the T-levers are so designed that, when a sensing member is raised (having sensed no hole in the tape) and the T-lever is brought into engagement with its projections, the upper projection will be struck by the upper arm of the T-lever which will turn the T-lever clockwise thus pulling a contact plate down if it had previously been in an up position. When a sensing member is in a lowered position (having sensed a hole in the tape) its lower projection is struck by the lower arm of a T-lever which turns the T-lever counter-clockwise thus raising a contact plate. After the five contact plates have been set pressure is applied to the group of plates bringing their contacts together and up against the common plate. A current pulse is caused to flow to the common plate where it seeks out the aligned contacts and flows through them to the terminal corresponding to the code'group in the perforated tape. Following the current pulse, a cam operated bail returns those sensingmembers which were left in a lowered position to the up position so the group will be ready to sense the next group of holes in the tape.

The following is a detailed description of the invention in order of operation. At the lower left of the mechanism, as illustrated in Figure 5, is a feed shaft 280 terminating in the knurled end 282. The other end of the shaft 2% is associated with a ratchet mechanism (not shown) which is driven by the cam shaft 198 to revolve the feed shaft 281 one code space for each onehalf revolution of the cam shaft 193. On the periphery of the feed shaft are sprocket teeth 284 for engaging the feed holes 286 of the tape 298. There are also five annular grooves 218 which are directly beneath each code hole position of the tape. Directly above each annular groove 210 is a sensing member 212, one for each code hole position in the tape. At the lower ends of the sensing members 212, cylindrical sensing pins 214 engage the code holes as the members 212 are lowered and raised by a means to be described. As they are lowered those that encounter holes pass on through and into the annular grooves 210 in the feed shaft. Each sensing member contains a pair of projecting arms 216 and 218 for engaging associated T-levers 116 and another projection 220 for engaging an oscillating bail 224. The upper end of each sensing member 212 has a spring 222 attached which will give the member a downward thrust.

Positioned to engage the bottom surface of the projections 228 is the bail 224 formed by a bent over part of an arm which is attached to the pivotally mounted post 226. The rear end of this post 226 has an arm 228 terminating in a cam follower 230. The arm 228 is biased in a clockwise direction by a spring 232 attached at its midpoint.

When the cam follower 238 is on the high part of the cam 234, the bail blade 224 is in its lower position and the sensing members which have encountered holes in the tape are pulled down by the springs 222. Those sensing members which have not encountered holes are held up by the unperforated paper.

After all of the sensing members 212 are set in their selected up and down positions, the outermost cam 236 on the cam shaft 198 presents a depression to a cam follower 238 on the end of a shaft 240 causing the cam follower to be suddenly turned counter-clockwise by the pull of the spring 241 secured to an extension thereof. This counter-clockwise turning is imparted to the shaft 249 the outer end of which carries an upwardly projecting transfer lever 114. As the transfer lever 114 turns with the shaft 248, a forwardly extending post 242 mounted at its upper end and having a group, of T-levers 116 equal in number to the sensing members and pivotally mounted thereon, is thrust to the left. The cross members of the T-levers 116 are provided at their extremities with knife edges 244 and 246 adapted to cooperate with knife edges 248 and 258 respectively, formed at the tips of projections 216 and 218 of the sensing members 212. When the arm 114 and post 242 are moved to the left as above described, the post 242 will enter the space between the projections 216 and 218 and thereby cause the knife edges 244 and 246 to cooperate with the knife edges of arms 216 and 213 and pivot on post 242 to simultaneously transfer the settings of all the sensing members to the corresponding T-levers 116. If a sensing member 212 has been moved to its lower position by its sensing pin 214 passing through a hole in the tape, the end 246 of the corresponding T-lever 116 will not strike the end 250 of its projection 213 but will pass beyond. Likewise if a sensing member 212 has been held up, the end 244 of the corresponding T-lever 116 will miss the end 248 of its projection 216. It is to be understood that, when the end 244 of a T-lever 116 misses the end 248 of a projection 216, the end 246 of that same T-lever will engage the projection'250 of the same associated sensing member, and vice versa, as the parts are so proportioned and positioned that one end must always mak engagement when the transfer takes place. i

The rightwardly projecting arms of the T-levers 116 terminate in rounded ends 118 which are located in elongated slots 120 of the extensions 28 of the correspond: ing ones of the group of five coded Contact plates 18, 20, 22, 24 and 26 as herein described. As the T-levers 116 pivot to assumethe position of the sensing members 212, the ends 118 willslide in the elongated slots 120 and also pivot therein to move" certain of the legs 28 up and others down in accordance with the positions of the associated T-levers 116. "The contact plates will slide up or down to assume their proper positions. When the five plates 18 have been set in their permuted positions as above described, their contacts are pressed together and against the common contact plate 38 by means of the pressure plate 42 and associated mechanism as described earlier. After the pressure has been applied, a current pulse is sent to the plate 38 by the closing of the contacts 186 by an upwardly projecting arm of the lever 184 acting through its cam follower. Contact is made when the cam follower is raised by the high part of the cam 182 and is timed to occur immediately after the cam follower on the'end of the bell crank 65 has dropped off its cam 72. As thecam shaft 198 continues to revolve, the cam follower 230 on the oscillating bail lever 228 will drop off the high part of its cam 234 and the associated bail 224 willraise the sensing members that had been in a lower position and the mechanism is ready to repeat its cycle for the next group of code perforations in the message tape.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in' all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. In a permutation selecting switch, a plurality of relatively shiftable two position selecting elements, contacts permutably arranged in said elements, selectively actuable electro-magnetic means for shifting any combination of said selector elements to establish an alignment of a set of contacts through said elements in accordance with the selective actuation of said electro-magnetic means, latching means for said selecting elements to retain said selecting means in their selected positions, and means for momentarily compressing said selecting elements to insure adequate electrical contact between said aligned set of contacts.

2. A mechanism as defined in claim 1 including means for restoring said selecting elements to their normal position.

3. In an electrical permutation switch, a set of relatively shiftable two position code elements, contacts'permutably arranged in said code elements, means for setting any combination of said elements in accordance with the permutations of a code to provide transverse alignment of said contacts individual to each relative setting of. said elements, an electrical terminal individual to each contact alignment, a common conducting plate for introducing an electric current to said contacts, a pressure plate, a pair of contiguous wedge-shaped members interposed between said pressure plate and said common conducting plate, means for longitudinally moving said pressure plate upon completion of the setting of said code elements to cause the cooperative sliding of said wedge members to compress the conducting plate and the aligned contacts of the 7 code elements to complete the selected electrical current conducting path. i, t v

4, In a permutation selecting device, a plurality of relatively shiftable selecting plates, contacts permutably arranged in said plates, and actuating means adapted to momentarily control and selectively set selected ones of said selecting plates in one of two positions to establish alignment of at least one series of contacts through said plates and thereafter to release control offsaid plates; means for maintaining each of said s electedpla'tes in their set position independently of the others of said plates and additional means coacting with said plates after they are released from control by said actuating means to provide an individual transverse electrically conductive path through the selecting plates. I

5. In a permutation switch, a group of contiguous relatively shiftable non-conducting plates, contacts permutably arranged in said plates, plate actuating means responsive to electrical signals for momentarily controlling and selectively positioning selected ones of said plates in one of two positions to so align certain of said contacts corresponding to each particular signal and thereafter to release control of said plates, means for maintaining each of said selected plates in their selected position independently of the others of said plates and additional means controlled independently of plate positions coacting with said plates after they are released from control by said actuating means to provide an electrically conductive path through said plates corresponding to said aligned contacts.

6. A circuit selector comprising a plurality of relatively shiftable selector elements, contacts permutably arranged in said selector elements, actuating means adapted to momentarily control and selectively set selected ones of said selector elements to establish alignment of at least one series of contacts through said elements and thereafter to release control of said elements, meansfor maintaining each of said selected elements in their set positions independently of the others of said selector elements and a source of current disconnected from said contacts during the setting of said selector elements, and means operable for all combinations of selector elements positions for connecting said source of current to said aligned series of contacts only after said selector elements have been set.

7. In an electrical permutation switch, a plurality of relatively shiftable contiguous code members, contacts permutatably arranged in each of saidcode members, actuating means adapted to momentarily control and shift said code members to establish a transverse contact alignment through the code members individual to each permutative arrangement thereof and thereafter to release control of said code members, means for maintaining said code members in their shifted position, electrical terminals for said contacts on one of said code members, a single contact connectable in common to all contacts of another of said code members, means including a first cam and a cam operator for momentarily compressing said code members between said terminals and said single common contact after saidcode members are released from control by said actuating means including a second cam and said cam operator, and means for energizing the electrical conductive path established by the aligned contacts.

8. In a permutation switch, a group of relatively shiftable code members, electrical contacts permutably arranged in said codemembers, actuating means adapted to momentarily controlandpermutably set said code members to align a set of said contacts to establish an electrically conductive path through said members peculiar to the setting of said code members and thereafter to release control said code members, means for maintaining each of said selected code members in their set position independently of the others of said code members, 'a stationary terminal plate in contiguity with one of said code members and having a plurality of individual electrical terminals, an electric conducting plate adjacent another of said code members, and means for moving said con- 8 r ducting plate intoen'gage ment with the contacts of said other code member to close the electrical current conducting path from said conducting plate through said aligned set of contacts to an associated terminal on said terminal plate. I V

9. An electrical switch comprising a plurality of adjacently disposed members mounted for relative movement in parallel paths, a plurality of independent electrical current conducting elements permutably mounted on said members and each extending through the member on which it is mounted, controllable actuating means for momentarily controlling and relatively positioning said members along their paths to establish an alignment of elements including an element on each of said mem bers and thereafter to release control of said members, means for maintaining each of said selected members in their set position independently of the other of said members and additional means coact-ing with said members after they are positioned by said actuating means to pro vide a positive individual transverse electrically conductive path through said aligned elements.

10. An electrical switch as defined in claim 9 wherein said controllable actuating means includes: a coded tape, a tape sensing device, and shifting means connected to saidtape sensing device and controlled thereby in accordance with the code in said tape for momentarily controlling and relatively positioning said members to establish an alignment of elements including an element on each of said memberswhereby said additional means will provide said electrically conductive path through said aligned elements peculiar to the code in the tape sensed by said tape sensing device.

ll. An electrical switch as defined in claim 9 wherein said controllable actuating means includes: an electric circuit over which coded groups of impulses are sent; an electro-magnet, including an armature, in said circuit for translating said coded impulses into corresponding movements of said armature; and a selecting mechanism responsive to said armature movement for momentarily controlling and relatively positioning .said members to establish an alignment of elements including an element on each of said members whereby said additional means will provide said electrically conductive path through said aligned elements peculiar to the coded impulses received by said electro'magnet. 7

12, In combination, a first electrical terminal, a second electrical terminal mounted in spaced relation to said first terminal, a plurality of electrical connectors mounted for individual movement in parallel paths intermediate said terminals, and controllable actuating means adapted to momentarily selectively control and individually position said connectors along their paths and thereafter to release control of said connectors, means for maintaining said selected connectors in their set position and additional means coacting with said connectors after they are released fromcontrol of said actuating means to permit the passage of electrical current through a selected transverse electrically conductive path from the first terminal to the second terminal through the connectors.

13. In an electrical permutation switch, a set of relatively shiftable code elements, contacts permutably arranged in said code elements, support means coacting with said elements for maintaining said elements in parallel spaced relation toeach other and enabling a selective parallel shifting of said elements relative to one another whereby the plates may be selectively arranged to provide one of a plurality of possible electrically conductive paths through a series of aligned contacts in said plates, a terminal plate fixed tosaid support means and having a plurality ofelectrieal terminals individual to each contact alignment, a common conducting plate mounted on said support mans for movement transverse to said parallel elements to thereby engage the contacts on one of said elements and compress all contact elements between said terminal plate and said conducting plate and for introducing an electric current to said contacts, a pressure plate mounted on said support means for parallel shifting movement relative to said contact elements and adapted to be selectively shiftable, and means between said pressure plate and said conducting plate for imparting a transverse movement to said conducting plate upon a shifting of said pressure plate.

14. A circuit selector comprising a plurality of relatively shiftable two position selector elements, contacts permutably arranged in said selector elements, selectively actuated electromagnetic means for selectively shifting each selector element into one of two positions to align a predetermined series of said contacts and to thereafter release control of said selector elements, means for individually maintaining selectively shifted elements in References Cited in the file of this patent UNITED STATES PATENTS 352,143 Munson Nov. 9, 1886 1,381,317 Loughridge June 14, 1921 1,937,983 Rugh Dec. 5, 1933 1,998,993 Kleinschmidt Aug. 23, 1935 2,675,425 Salmon Apr. 13, 1954 

